JPH1025565A - Production of head thin film and hard thin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing hard thin film having high hardness and utilizable as a hard material and a superhard material at a high speed and at a low cost and to provide the hard thin film having high hardness. SOLUTION: As for the method for producing hard thin film, a cathode incorporated with a carbon source at least contg. carbon and a base metal are used, and hard thin coating is produced by an arc ion plating method. In this case, negative bias voltage is applied to the base metal to regulate the base metal to the negative potential, and the space between the cathode and base metal is provided with a protective body preventing molten carbon grains having >=0.1μm grain diameter among the carbon evaporated from the carbon source from depositing on the base metal. By this producing method, the hard thin film having high hardness can be produced, and this thin film is excellent as a hard material and a superhard material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard thin film which can be used as a hard material and a super hard material, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, hard thin films widely used industrially include TiN, TiC, Si ₃ N ₄ , SiC and Al _2.
There is a thin film made of a hard material such as O ₃ or WC, and its Knoop hardness (Hk) is 1500 to 3500. Further, there are three types of crystalline materials, which are called super-hard materials, as materials having higher hardness than these hard materials. In order of hardness, diamond (C) (Hk8000
-10,000), cubic boron nitride (c-BN) (Hk
4000-6000), boron carbide (B ₄ C) (Hk3
500-4500).

In recent years, attempts have been made to produce ultra-hard materials containing carbon, nitrogen and boron as components.
In particular, many attempts have been made to produce ultra-hard materials containing carbon as a main component. Among diamond-like carbon (DLC; amorphous carbon (aC: H)), sp ³ -C
One having many components and particularly hard) is one example. Recently, theoretical calculation results show that carbon nitride represented by the composition formula of the virtual substance β-C ₃ N ₄ has a high bulk modulus comparable to that of diamond described above (AY Liu and
M. L. Cohen, Science, 245 (198
9) 841) was reported, and carbon nitride has also become available as an ultra-hard material.

Therefore, attempts have been made to produce such a DLC thin film or carbon nitride thin film using various PVD and CVD processes. In the PVD method, for example, graphite is evaporated by an electron gun to perform vacuum deposition of a carbon film on a substrate, and nitrogen ions are implanted into the deposited film by an ion beam to produce an amorphous carbon nitride thin film. A method is disclosed, and there is a report that a hard thin film having high hardness was obtained (F. Fujimoto and
K. Ogata, Jpn. J. Appl. Phys. ,
76 (1994) 3791. ). In the CVD method,
There is a report that a hard thin film made of carbon nitride was obtained by capacitively coupled high-frequency plasma CVD using a hydrocarbon and N ₂ gas (P. Wood, T. Wydeven).
andO. Tsuji, Thin Solid Fil
ms, 258 (1995) 151. ).

[0005] However, the conventional method for producing a hard thin film such as a DLC thin film or a carbon nitride thin film has the disadvantage that the film forming speed is low and the time spent for producing the thin film is long. It has also been difficult to form a large-area thin film or to form a thin film on a three-dimensionally complex base material. On the other hand, by arc ion plating using a cathode evaporation source,
Hard thin films such as TiN have been produced. According to this method, a thin film can be formed at a high film forming rate, and a thin film having a large area can be formed or a thin film can be formed on a base material having a three-dimensionally complex shape. However, in this method, molten particles having a particle diameter of 0.1 μm or more from the cathode evaporation source are also evaporated. Therefore, in this method,
When a carbon source containing carbon is used as a cathode evaporation source, and particularly when graphite is used as a raw material of the carbon source, molten carbon particles having a particle size of 0.1 μm or more larger than the carbon source also evaporate. The molten carbon particles having a particle size of 0.1 μm or more are hardly excited or ionized in the arc plasma, and are substantially different from other substances (similar substances and other substances contained in the arc plasma). Fly directly onto the base material as it is without any synthetic reaction. When the molten carbon particles deposit on the base material, a thin film having high hardness cannot be obtained.

Accordingly, in such an arc ion plating method, a curved tube is used, a cathode provided with a carbon source is provided at one end of the curved tube, and a base material is provided at the other end. A method for producing an amorphous carbon thin film by bending an arc plasma generated between them by magnetic force is disclosed (R. Lossy, DLP).
appas, R .; A. Roy, J .; P. Doyle,
J. J. Cuomo and J.M. Bruley, J .;
Appl. Phys. 77 (1995) 4750).

In the arc ion plating method using the curved tube, the molten carbon particles moving linearly in space are trapped in the curved portion of the curved tube, and the molten carbon particles are devised so as not to deposit on the base material. ing. However, since a curved tube and a magnet for bending the arc plasma are required, not only the cost is increased but also the area of the thin film to be formed and the shape of the base material are limited.

[0008]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a hard thin film having high hardness and excellent lubricity, adhesion resistance, abrasion resistance, and surface smoothness. It is an object of the present invention to provide a manufacturing method that can be manufactured at high speed and at low cost, and that can form such a hard thin film into a large-area thin film or a base material having a three-dimensionally complicated shape. .

[0009] A hard thin film obtained by this manufacturing method, which has high hardness, lubricity, adhesion resistance,
An object of the present invention is to provide a hard thin film which has excellent wear resistance and surface smoothness and can be used as a hard material and a super hard material.

[0010]

Means for Solving the Problems The present inventor uses a conventional arc ion plating method to apply a negative bias voltage to a base material to a negative potential and to reduce the amount of carbon evaporating from a carbon source to zero. By forming a thin film by providing a protective body between the carbon source and the base material so that molten carbon particles having a particle size of 1 μm or more do not deposit on the base material, the hardness is high, and the lubricity and the resistance are improved. The present inventors have found that a hard thin film having excellent adhesion, abrasion resistance, and surface smoothness can be obtained, which has led to the present invention.

That is, the method for producing a hard thin film of the present invention is a method for producing a hard thin film by an arc ion plating method using a cathode having a carbon source containing at least carbon and a base material, A negative bias voltage is applied to the base material to bring the base material to a negative potential, and 0.1% of the carbon evaporating from the carbon source between the cathode and the base material.
A protection body is provided to prevent molten carbon particles having a particle size of 1 μm or more from depositing on the base material.

Further, the hard thin film of the present invention uses a cathode having a carbon source containing at least carbon and a base material, and applies a negative bias voltage to the base material to make the base material a negative potential. And a protector is provided between the cathode and the base material to prevent molten carbon particles having a particle size of 0.1 μm or more from being deposited on the base material among the carbon evaporated from the carbon source. state in a rigid thin film obtained by the arc ion plating method, a plurality of sp ³ -C is sp ³ -C domain and a plurality of sp ² -C bound formed each other are combined with each other to form and amorphous carbon network and sp ² -C domain is formed by combining at random, and the hydrogen atoms bonded to at least a portion of carbon atoms constituting the amorphous carbon network, consisting of a-C: Characterized in that it is a thin film.

Further, another hard thin film of the present invention is:
A hard thin film obtained by the same method as the hard thin film that is the aC: H thin film, wherein a plurality of sp ³ -C domains formed by bonding a plurality of sp ³ -C to each other and a plurality of sp ^2-
An amorphous carbon network formed by randomly bonding sp ² -C domains formed by bonding C atoms to each other; and nitrogen substituted by at least a part of carbon atom sites constituting the amorphous carbon network. And an aC: N thin film composed of atoms.

The arc ion plating method used in the method for producing a hard thin film of the present invention is a method for producing a thin film on a base material using an arc plasma using a cathode having a target. In this method, the target surface is heated by the high heat of the arc plasma, and the substance contained in the target evaporates, and a part of the evaporating substance receives energy from the plasma and is excited or ionized, or other substances in the arc plasma are excited. (Similar substances and other substances contained in arc plasma). Then, the evaporated substance is deposited on the base material in such a form as when evaporated, in a form excited and ionized in the arc plasma, and in a form where it has undergone a synthetic reaction with other substances in the arc plasma, and is included in the target. A thin film containing the substance is formed on the base material. Arc plasma is characterized by a high ionization rate, and by using this arc ion plating method, a hard thin film can be formed at a high film forming rate.

In the present production method, since a carbon source containing at least carbon is used as a target, the particle size of carbon atoms, carbon molecules, carbon clusters, etc. is 0.1 μm from the surface of the carbon source.
small carbon species with a particle size of less than 0.1 m
Large molten carbon particles having a particle size of m or more evaporate. Since the large-diameter molten carbon particles have a large mass, they move linearly in the arc plasma almost without being affected by collision of small-mass particles existing in the arc plasma. On the other hand, a carbon species having a small particle diameter of less than 0.1 μm has a small mass, and thus changes its moving direction and speed due to collision with particles in arc plasma or the like.

[0016] For this reason, such large molten carbon particles having a particle diameter of 0.1 µm or more fly straight and adhere to the protective body provided between the cathode and the base material. On the other hand, small carbon species having a particle size of less than 0.1 μm have a behavior that is not linear, and some of them adhere to the protective body. In the form excited and ionized by the above and in a form synthesized and reacted with other substances in the arc plasma, it wraps around the protective body and deposits on the base material. This protector prevents molten carbon particles having a particle size of 0.1 μm or more from depositing on the base material, and forms, excites, and ionizes small carbon species having a particle size of less than 0.1 μm when evaporated. It can be deposited on the base material in such a form that it has undergone a synthesis reaction with other substances.

In the present manufacturing method, the base material is a negative via.
Voltage is at a negative potential, causing arc plasm
Of the positive ions existing at high density in the
The existing positive ions receive Coulomb force from the base material.
The positive ions that have received the Coulomb force are the surface of the base material.
It is attracted to the part, accelerates, and enters the growth film surface.
Higher energy of the incident positive ions
Gives high impact energy to the growth film surface. This opposition
The spike energy causes sp ^Three-C
Production is enhanced and these sp^Three-C are linked together
Sp of the magnitude of short-range order^Three-C domain is formed
You. The sp thus formed^Three-The C domain is
Sp of the size of the formed short-range order^Two-C domain and
Amorphous carbon network with random bonding
Is formed.

If the molten carbon particles having a particle diameter of 0.1 μm or more are deposited at this time, carbon which cannot receive the impact energy of the positive ions incident on the surface of the grown film increases, and sp ³ -C is formed. Is inhibited by sp ³
-The formation amount of the C domain is reduced. Further, irregularities of 0.1 μm or more are generated on the surface of the grown film, and the smoothness of the film surface is deteriorated. In the present manufacturing method, the protective body is used for the purpose of 0.1.
Since the deposition of molten carbon particles having a large particle diameter of 1 μm or more can be prevented, it is possible to prevent such a decrease in the formation amount of the sp ³ -C domain and deterioration of the smoothness of the film surface.

The hard thin film of the present invention is produced by the method of the present invention, and has a high hardness because it contains sp ³ -C domains, and has lubricity and anti-adhesion properties because it contains sp ² -C domains. It has excellent wear resistance due to the effect of containing both sp ³ -C domain and sp ² -C domain, and has excellent surface smoothness due to its amorphous structure.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the method for producing a hard thin film according to the present invention, a carbon source, a base material, and a protective body are respectively installed in containers capable of generating arc plasma. A carbon source is provided at the tip of the cathode and serves as a target for arc plasma. The base material is installed in a direction in which carbon evaporates from the carbon source, and is installed such that the surface of the base material forming the hard thin film is at least in arc plasma. The defense body is installed at a position between the carbon source and the base material. A plurality of carbon sources, a base material, and a protective body may be provided as necessary to form a thin film. In this manufacturing method, the size of the spatial spread of the arc plasma can be arbitrarily changed by selecting the size of the container or the size of the cathode.

The carbon source containing at least carbon used in the present production method is not particularly limited, but it is preferable to use graphite. Graphite is an easy and safe material to handle. Further, even a high-purity material is inexpensive and has electrical conductivity, so that it can be used as a constituent member of a cathode electrode. Therefore, it is very excellent as a carbon source material. By providing a carbon source made of graphite on at least a part of the surface of the cathode electrode, the particle diameter of carbon atoms, carbon molecules, carbon clusters, etc. is smaller than 0.1 μm from the carbon source by arc plasma. It can be evaporated with a large amount of small carbon species. Then, these carbon species are excited to receive energy from the plasma when passing through the arc plasma, also some of _{^{ionized, C *, C 2 *,}} C 2 +, excitation of C ^+, etc., The ionized carbon species spreads in the plasma.

At this time, it is desirable to vaporize carbon from the carbon source by using at least one of an electron beam, a laser, and an ion beam. By combining these methods, it is possible to evaporate a carbon species having a higher density and a smaller particle size of less than 0.1 μm, and to increase the number of carbon species excited and ionized in the arc plasma.

It is desirable that the arc plasma used in the present manufacturing method contains at least hydrogen. As such arc plasma, hydrogen _{^{H *, H 2 *, H}} 2 +, H
Those in an excited and ionized form such as ⁺ can be used. Since the hydrogen in such a form is in a highly reactive state, it easily reacts and bonds with carbon evaporated from the carbon source. At this time, the pressure in the system is 0.01P
It is more desirable that the pressure be not less than a and not more than 30 Pa. Due to the pressure in the system, hydrogen in an excited and ionized form is present in the arc plasma at a higher density.

By using such an arc plasma containing hydrogen, a sp ³ -C domain formed by combining a plurality of sp ³ -C and a plurality of sp ² -C are formed by combining with each other. The sp ² -C domain is simultaneously formed on the grown film, and an amorphous carbon network in which the sp ³ -C domain and the sp ² -C domain are randomly bonded is formed. At this time, at the same time as the formation of the amorphous carbon network, hydrogen atoms bond to some of the carbon atoms constituting the amorphous carbon network. Thus, the sp ³ -C domain and s
an aC: H thin film comprising an amorphous carbon network formed by randomly bonding to p ² -C domains and hydrogen atoms bonded to at least a part of carbon atoms constituting the amorphous carbon network Is formed.

At this time, the negative bias voltage applied to the base material is desirably in the range of -50V to -300V. As a result, many sp ³ -C domains are formed,
The hardness of the thin film increases. This negative bias voltage is -5
If the absolute value is smaller than 0 V, the incident positive ions are not sufficiently accelerated, and the amount of energy supply to the surface of the grown film is reduced, and the amount of sp ³ -C domain formed is undesirably reduced. The large and cause excessive ion bombardment in absolute value than -300 V, sp from sp ³ -C Domain ² -
The formation of the C domain is not preferred because it predominates.

Alternatively, it is desirable that the plasma used in the present manufacturing method contains at least nitrogen. As such arc plasma, nitrogen is _{^{N *, N 2 *, N}} 2 +,
Excited and ionized forms such as N ⁺ can be used. Since nitrogen in such a form is in a highly reactive state, it readily reacts with and bonds to carbon evaporated from a carbon source. At this time, it is more desirable that the pressure in the system be 0.01 Pa or more and 30 Pa or less. Due to the pressure in the system, nitrogen in the excited and ionized form is present in the arc plasma at a higher density.

An arc plasma containing such nitrogen is used.
By having multiple sp^Three-C are bonded to each other
Sp created^Three-C domain and multiple sp^Two-C are each other
Formed by bonding to^Two-C domain and
Formed on long film, sp^Three-C domain and sp^Two-C
Amorphous carbon
A network is formed. At this time, the amorphous car
At the same time as the formation of the bon network,
One of the carbon atom sites that make up the
Part is replaced by a nitrogen atom. Thus, sp^Three-C
Domain and sp ^Two-C domain binds randomly
The formed amorphous carbon network and the
Carbon sources that make up the morphus carbon network
A nitrogen atom substituted for at least a part of a child site,
The resulting aC: N thin film is formed.

At this time, it is desirable that the negative bias voltage applied to the base material is in the range of -100V to -400V. Thus, as in the case of the aC: H thin film, sp ³
Many -C domains are formed, and the hardness of the thin film increases. If the negative bias voltage is smaller than -100 V in absolute value or larger than -400 V in absolute value, it is not preferable for the same reason as the aC: H thin film.

Alternatively, in the present manufacturing method, it is desirable to use an arc plasma containing at least one of helium, neon, argon, krypton, and xenon. Also by using such plasma, a sp ³ -C domain and sp ² -C domain is formed simultaneously on the base material, Alfaz carbon and sp ³ -C domain and sp ² -C domains randomly bonded A network is formed.

In the present manufacturing method, the method of generating the arc plasma is not particularly limited.
Arc discharge by applying a DC low voltage and high current between the anode and the cathode through a low pressure gas containing hydrogen gas, nitrogen gas, or a rare gas such as helium, neon, argon, krypton, xenon, etc. Can be caused to occur.

The material of the base material used in the present manufacturing method is not particularly limited, but it is preferable to use a material made of at least one of a metal, a semiconductor, a ceramic, and a resin. These materials are widely used industrially, and are also used for members and the like that require particularly high mechanical properties. At this time, the base material can be set to a negative potential by applying a negative bias to the conductive base material using a DC voltage source or the like. On the other hand, with respect to an insulating base material, the base material can be set to a negative potential by negatively self-biasing the base material using a high-frequency power supply or the like.

The surface area and shape of the base material are not particularly limited, but a hard thin film can be formed on a base material having a large surface area or a base material having a three-dimensionally complex shape. Then, the base material is usually fixed to form a hard thin film, but when the thickness or the like of the surface is uneven due to the size or shape of the surface area, the base material is rotated or moved linearly to prevent this, A hard thin film can be manufactured by moving it two-dimensionally or three-dimensionally so that the film thickness does not become uneven.

Further, the material and shape of the protective body used in the present manufacturing method are not particularly limited, but it is preferable that the protective body is made of at least one of metal and ceramics and is a plate-like protective plate. Since the protective body is made of metal, the potential of the protective body can be controlled, and since it is made of ceramics, durability against high-temperature arc plasma is improved. In addition, by using a plate-shaped defense plate as the protection body, it becomes excellent in simplicity.

Regarding the size of the protective body, when the protective body is installed at a predetermined position between the carbon source and the base material, at least the surface of the base material forming a hard thin film as viewed from the carbon source is the protective body. Use a size that is completely hidden behind. Accordingly, it is possible to prevent large molten carbon particles having a particle size of 0.1 μm or more from being deposited on the base material. On the other hand, if the size is larger than necessary, it is not preferable because carbon atoms, carbon molecules, carbon clusters and other small carbon particles having a small particle size are prevented from wrapping around.

Further, it is desirable that the protective body is at 0 V or a positive potential. As a result, it is possible to prevent the generation of electrostatic attraction between the protective body at 0 V or a positive potential and the positive carbon ions in the arc plasma. In particular, by setting the protective body to a positive potential, a repulsive force is generated between the protective body and positive ions in the arc plasma, and the amount of the ionized carbon species wrapping around the protective body increases.
On the other hand, if the potential of the protective body is made negative, the amount of carbon species ionized in the arc plasma attached to the protective body increases, and the amount of ionized carbon species in the arc plasma decreases. At this time, in particular, the amount of ionized carbon species in the arc plasma between the protector and the base material decreases, so that the amount of carbon deposited on the base material decreases, and the film forming speed can be increased. And the ion bombardment cannot be effectively applied to the grown film.

[0036]

According to the method for producing a hard thin film of the present invention, molten carbon particles having a particle diameter of 0.1 μm or more, which evaporate from a carbon source, do not accumulate on a base material and sp ³ -C domains The sp ² -C domain is formed simultaneously and sp ³
-C domain and sp ² -C domain are randomly bonded to form an alphas carbon network, so that the hardness is large, and the lubricating property, adhesion resistance, abrasion resistance,
A hard thin film having excellent surface smoothness can be obtained.

In particular, in the present manufacturing method, by using an arc plasma containing at least hydrogen, an amorphous carbon network formed by randomly bonding sp ³ -C domains and sp ² -C domains, And a hydrogen atom bonded to at least a part of the carbon atoms constituting the network.
A C: H thin film can be manufactured.

Alternatively, by using an arc plasma containing at least nitrogen, an amorphous carbon network formed by randomly bonding sp ³ -C domains and sp ² -C domains, and the amorphous carbon network are formed. A nitrogen atom at least partially substituted for a carbon atom site
A C: N thin film can be manufactured.

These aC: H thin films and aC: N thin films contain a large amount of sp ³ -C domains, and therefore have extremely high hardness. Further, the pressure in the system is set to 0.01 Pa or more and 30 Pa or less, and a negative bias voltage applied to the base material is selected to sp.
By forming many ^3- C domains, a hard thin film having higher hardness can be obtained. Also, in the present manufacturing method,
Since the film formation rate can be increased, a hard thin film having high hardness such as an aC: H thin film and an aC: N thin film can be formed at a high speed. Also, since the size of the spatial spread of the arc plasma can be changed arbitrarily,
A thin film having a desired area can be formed or a thin film can be formed on a base material having a desired shape in accordance with the spatial spread of the arc plasma. Further, a hard thin film having an arbitrary thickness can be formed depending on the film formation time.

[0040]

The present invention will be described below in detail with reference to examples. (Preparation of Sample) In the present embodiment, a multi-arc coating device (MAV-
15.2), a carbon source made of graphite sintered body (Toyo Tanso IG510, ash: 10 ppm) as a carbon source of carbon, and a substrate (16 mm × 40 mm, thickness: (0.5 mm) to produce a hard thin film.

FIG. 1 shows a schematic view of an apparatus for producing a hard thin film used in this embodiment. The hard thin film was made of stainless steel (SUS304) and had a height of 512 mm and a width of 415.
mm and a depth of 410 mm in a vacuum container 1 having a volume of 410 mm. The vacuum vessel 1 can maintain a degree of vacuum of up to 10 ^-4 Pa by evacuation by a vacuum pump. A cylindrical carbon source 2 (φ6
4 mm × 32 mm) is attached to the opposite side of the exhaust port 3 and is fixed so as not to touch the inner wall of the vacuum vessel 1. Further, a substrate holder 4 made of stainless steel and a plate-like protective body 5 made of stainless steel (70 mm × 40 m
m, thickness 3 mm) is fixed on a mounting table 6 made of stainless steel. The substrate 7 is fixed by the substrate holder 4. In the preparation of the sample in this embodiment, the protective body 5 is fixed at a predetermined distance between the evaporating surface of the carbon source 2 and the protective body 5, and a distance of 40 mm is provided between the protective body 5 and the substrate 7. After that, the substrate 7 was fixed on the mounting table 6.

The vacuum vessel is grounded, and a direct current source 8 provided outside the vacuum vessel 1 uses the vacuum vessel 1 as an anode, the carbon source 2 as a cathode, and the bottom of the vacuum vessel 1 and the carbon source 2. It is connected between. A DC voltage source 9 for applying a negative bias voltage to the substrate 7 is provided outside the vacuum vessel 1 and is connected between the vacuum vessel 1 and the substrate 7.

Further, a hydrogen gas supply source 10 and a nitrogen gas supply source 11 are attached to the vacuum vessel 1. The hydrogen gas supply source 10 supplies the vacuum vessel 1 with a high purity of 99.99999%. H ₂ gas is introduced, and purity of 99.9 is supplied from the nitrogen gas supply source 11 into the vacuum vessel 1.
999% high purity N ₂ gas is introduced. Further, a ring-shaped permanent magnet 12 is attached to the outside of the vacuum vessel 1 behind the carbon source 2. Also, a ring-shaped iron disc 13
Are attached to the position shown in FIG. 1 via a ring-shaped space so as not to contact the carbon source 2. Lines of magnetic force radially emitted from the permanent magnet 11 pass through the front side from the back side of the carbon source, converge on the substrate side surface of the iron disk 13 in an arc. The arc plasma moves under the action of the lines of magnetic force, and the contact point with the surface of the carbon source 2 moves, so that the unevenness of the evaporation surface of the carbon source 2 is reduced.

The substrate 7, which has been well washed and dried using an alkaline solution, ion-exchanged water and ethanol, is fixed to the substrate holder 4, and the air in the vacuum vessel 1 is exhausted by a vacuum pump to reduce the degree of vacuum to 10 ^-3. Pa and then the hydrogen gas source 1
H ₂ gas having a purity higher than 0 is introduced into the vacuum vessel 1, and the amount of H ₂ gas discharged from the hydrogen gas supply source 10 and the amount of H ₂ gas discharged from the hydrogen gas supply source 10 are adjusted by adjusting the amount of H ₂ gas exhausted by the vacuum pump. _{(2) The} gas pressure was set to 1 Pa, and this pressure was kept constant. Further, a predetermined negative bias voltage was applied to the substrate 7 by the DC voltage source 9 to set the substrate 7 to a negative potential. Subsequently, the DC current source 8
To make the potential of the carbon source 2 -50 to -100 V,
Arc discharge is caused by the current of
4 was generated. At this time, the protection body 5 and the substrate 7 were in a state in the arc plasma 14. Then, the current of the DC current source 8 was kept constant at 60 A to perform arc discharge, thereby producing a thin film.

At this time, the predetermined distance between the evaporating surface of the carbon source 2 and the protective body 5 is 160 mm, and the predetermined negative bias voltages applied to the substrate 7 are -50 V and -100 V, respectively.
V, -200V, -300V, -400V, -500V
The samples of six types of hard thin films were prepared by selecting from Examples 1 and 2, and the samples were referred to as Example 1, Example 2, Example 3, Example 4, Example 5, and Example 6, respectively. In addition, a sample of a (0 V) thin film was prepared without applying a negative bias voltage to the substrate 7, and was set as Comparative Example 1. The temperature of the substrate 7 was 200 ° C. or less when measured using an alumel-chromel thermocouple 15.

High-purity N ₂ gas is introduced into the vacuum vessel 1 from the nitrogen gas supply source 11 to reduce the N ₂ gas pressure in the vacuum vessel 1 to 1
Pa, the predetermined distance between the evaporation surface of the carbon source 2 and the protective body 5 is 120 mm, and the predetermined negative bias voltages applied to the substrate 7 are -100 V, -150 V, and -2, respectively.
Except for selecting from 00V, -300V, -400V, and -500V, samples of hard thin films were prepared in the same manner as in Examples 1 to 6.

The predetermined negative bias voltages applied to the substrate 7 are set to -100 V, -150 V, -200 V, and -30 V, respectively.
Samples of six types of hard thin films prepared at 0 V, -400 V, and -500 V were used as Example 7, Example 8, Example 9, Example 10, Example 11, and Example 12, respectively. In addition, a sample of a (0 V) thin film was prepared without applying a negative bias voltage to the substrate 7, and was set as Comparative Example 2. The substrate temperature is
When measured using an alumel-chromel type thermocouple 15, the temperature rose to 200 ° C. or lower. (Evaluation of Samples) For the samples obtained in Examples 1 to 12 and Comparative Examples 1 and 2, the film thickness was measured by using the stylus method, and the film forming rate was obtained from the film thickness and the film forming time. . As a result, it was found that the samples obtained in Examples 1 to 12 and Comparative Examples 1 and 2 were produced at a deposition rate of 200 nm / min.

The hardness of each of the samples obtained in Examples 1 to 12 and Comparative Examples 1 and 2 was measured.
This hardness measurement is performed using a dynamic ultra-micro hardness tester (Shimadzu DUH-
200), a diamond triangular pyramid indenter having an edge angle of 115 ° was pressed into the thin film surface on the substrate 7 with a load of 0.5 gf to obtain a hardness equivalent to only plastic deformation of the sample.

FIG. 2 shows the results of hardness measurement of the samples obtained in Examples 1 to 6 and Comparative Example 1. FIG. 3 shows the results of hardness measurement of the samples obtained in Examples 1 to 6 and Comparative Example 1. 2 and 3, FIG.
The hardness of the substrate 7 of Si (100) measured by the main measurement is shown for comparison. This Si (100) has a Knoop hardness of 1400 (Hk).

FIG. 2 shows that the hardness of the sample of Comparative Example 1 was Si.
It can be seen that the hardness is lower than (100). -50 to -3
The samples of Examples 1 to 4 produced by applying a negative bias voltage in the range of 00 V to the substrate have higher hardness than Si (100), and the samples of Examples 5 and 6 have a hardness of Si (100).
It turns out that it is almost the same as (100). This indicates that the samples of Examples 1 to 6 have extremely high hardness, and the samples of Examples 1 to 4 are particularly excellent as hard materials. In particular, the sample of Example 2 produced by applying a negative bias voltage of −100 V to the substrate 7 has a hardness twice as high as that of the Si substrate, and is a hard thin film having excellent hardness as a hard material.

FIG. 3 shows that the hardness of the sample of Comparative Example 2 was Si.
It can be seen that the hardness is lower than (100). On the other hand, -10
The samples of Examples 7 to 11 produced by applying a negative bias voltage in the range of 0 to -400 V to the substrate 7 have higher hardness than Si, and the sample of Example 12 is almost the same as Si (100). You can see that. From this, Example 7
Samples Nos. To 12 had extremely high hardness, and among them, Examples 7 to
It can be seen that the sample No. 11 is excellent as a hard material. In particular, it can be seen that the sample of Example 10 manufactured by applying a negative bias voltage of -300 V to the substrate has four times the hardness of the Si substrate. This is a hardness that can be sufficiently used as a super-hard material.

Next, the samples obtained in Examples 1 to 12 and Comparative Examples 1 and 2 were subjected to X-ray photoelectron spectroscopy (X
PS), the chemical composition of the thin film was examined, and the atomic ratio of nitrogen and carbon (N / C ratio) was determined. Furthermore, X-ray diffraction (XR
D), structural analysis was carried out using Raman spectroscopy and infrared spectroscopy (IR) together, and surface observation was carried out using an atomic force microscope.

As a result of examining the chemical composition of the thin film by XPS, it was found that the samples of Examples 1 to 6 and Comparative Example 1 had carbon as a main component. On the other hand, it was found that the samples of Examples 7 to 12 and Comparative Example 2 consisted of only carbon and nitrogen. Moreover, as shown in FIG. 4, it turned out that the N / C ratio of the sample of Examples 7-12 and the comparative example 2 is 0.16-0.32.

Although the XRD measurement results are not shown, the measurement results show that the samples obtained in Examples 1 to 12 and Comparative Examples 1 and 2 were amorphous. The samples of Examples 1 to 12 and Comparative Examples 1 and 2 were measured for Raman scattering spectra with respect to an argon laser having a wavelength of 514.5 nm. FIG. 5 shows Raman spectra obtained for the samples of Examples 1 to 6 and Comparative Example 1.
Shown in Further, a thin film sample made of only graphite-like sp ² -C was prepared under the same preparation conditions as in Example 9 except that the protective body 5 was not used, and the Raman spectrum thereof is shown in FIG. Was. Examples 7 to 12
FIG. 6 shows the Raman spectrum obtained for the sample of Comparative Example 2 and FIG. In FIGS. 5 and 6, the horizontal axis represents Raman shift (cm ⁻¹ ), and the vertical axis represents relative values of Raman scattering intensity.

First, Comparative Example 3 will be described. If the graphite has good crystallinity, the wave number is 1575 to 158.
Only one sharp peak corresponding to the E ₂ g mode appears around 0 cm ⁻¹ (this peak is called G band). On the other hand, since the thin film sample of Comparative Example 3 had poor crystallinity, the G band was broad, and the peak at which the crystallite size was reduced to 1350 cm ⁻¹ and Raman activity was reached. Appears (this peak is D
Called a band). This thin film is made of graphite sp
^{Since the} network is formed only with ^2- C, there is no change in the peak position of the G band. And the D band is s
This corresponds to only the network irregularity of p ² -C. FIG.
As more apparent in the samples of Examples 1 to 6 and Comparative Example 1, since the incoming sp ³ bonding component by sp ³ -C, G band due to graphite specific sp ² -C network further broad , And shifts to the lower wave number side from the original position (1575-1580 cm ^-1 ). On the other hand, the D band, not only the size of the graphite crystallites is reduced, also due to the fact that irregularities occur in a graphite coupling angle due to incoming sp ³ bonding component by sp ³ -C . From these results, in the samples of Examples 1 to 6 and Comparative Example 1, sp
³ and a -C domain and sp ² -C domain, it can be seen that these domains form a carbon network randomly bonded.

Among the examples 1 to 6, the Raman spectra of the examples 2 and 3 have a band shape peculiar to the DLC. 2 has the highest hardness. −300
At a negative bias voltage whose absolute value is larger than V, the G band gradually shifts to a graphite-like position, and the peak width gradually narrows. This is because, if an excessive negative bias is applied to the substrate, the graphite-like s
This shows that the p ² -C domain is formed relatively more than the sp ³ -C domain.

[0057] Also from FIG. 6, in the sample of Example 7-12, the broad peak of G-band near 1570～1560Cm ^-1, it can be seen that the broad peak of D band near 1370～1360Cm ^-1 is observed. From these results, the samples of Examples 7 to 12 and Comparative Example 2 showed sp ³
-C domain and sp ² -C domain, and it can be seen that these domains bind randomly to form a carbon network.

Next, the results of measuring infrared transmission absorption spectra of the samples of Examples 1 to 12 and Comparative Examples 1 and 2 will be described. Although the samples of Examples 1 to 6 and Comparative Example 1 are not shown, it can be seen that in any of the samples, an infrared absorption edge can be seen near a wave number of 2800 to 3000 cm ⁻¹ , and carbon and hydrogen are bonded. I knew it was there. From this, it can be seen that in each of the samples of Examples 1 to 6 and Comparative Example 1, a hydrogen atom is bonded to the terminal portion of each of the sp ³ -C domain and the sp ² -C domain.

FIG. 7 shows infrared transmission absorption spectra measured for the samples of Examples 7 to 12 and Comparative Example 2. In FIG. 7, the wave number (cm ^-1 ) of the infrared light transmitted through the sample is shown.
Is plotted on the horizontal axis and the relative value of the infrared transmission spectrum intensity is plotted on the vertical axis. From FIG. 7, in each of the samples,
2215 cm ^-1 , 1620-1590 cm ^-1 , 1540
-1520 cm ^-1 , 1380-1250 cm ^-1 , 136
Infrared absorption edges are observed near six wave numbers of ⁰ to 1180 cm ^-1 and 1090 to 1080 cm ^-1 . 2215cm
^{The -1} infrared absorption is due to the cyanamide-like or also benzonitrile-like C≡N bond as the terminal part of the network. 1620-1590 cm ^-1 and 1
The infrared absorption at 540 to 1520 cm ^-1 is a combination of a pyridine-like C = C bond and a C = N bond,
That is, it depends on the conjugate state. Also, 1380-1
The infrared absorption at 250 cm ⁻¹ is due to an aniline-like C—N bond. The weak infrared absorption around 1090-1080 cm ^-1 is due to the CN bond of the primary aliphatic amine. Accordingly, it can be seen that the sp ² -C domains of Examples 7 to 12 include pyridine-like, aniline-like, and first aliphatic structures in addition to the graphite-like structure.

From the results of the composition analysis and the structural analysis,
The samples of Examples 1 to 6^Three-C domain and sp
^Two-Amorphous moss with random bonding to C domain
Hydrogen in these domains
Consists of aC: H bonded to the terminal part of
You. That is, sp.^Three-C domain and s
p ^Two-A domain formed by random bonding with the C domain
A morphous carbon network and the amorphous carbon
At least the carbon atoms that make up the carbon network
AC: H thin film consisting of a hydrogen atom partially bonded to
It can be seen that can be manufactured.

The samples of Examples 7 to 12 were sp ^3-
It can be seen that the amorphous carbon network in which the C domain and the sp ² -C domain are randomly bonded is formed of aC: N in which the carbon atom sites constituting the network are substituted with nitrogen atoms. That is,
According to the present production method, the amorphous carbon network formed by randomly bonding the sp ³ -C domain and the sp ² -C domain, and at least a part of the carbon atom sites constituting the amorphous carbon network are substituted. It can be seen that an aC: N thin film composed of the nitrogen atoms formed can be manufactured.

In the samples of Examples 7 to 12, Liu et al.
Β-C which is an example of calculation of_ThreeN_FourThe structure of is formed
It is hard to say that these consist of hydrogenated carbon and carbon nitride
The increase in hardness of the thin film is due to sp^Three-C domain
According to In this embodiment, sp^Three-Quantification of C domain
Although not performed, the higher the hardness of the sample, the higher the sp ^Three
It is thought to contain many -C domains.

Further, among the samples of Examples 1 to 6, the samples of Examples 5 and 6 have a relatively small hardness as compared with the samples of Examples 1 to 4, and the samples of Examples 7 to 12 have a relatively low hardness. It can be seen that the sample of Example 12 has relatively lower hardness than the samples of Examples 7 to 11. This is considered to be because the magnitude of the negative bias voltage of the base material was excessive, and the temperature of the base material surface was excessively increased due to excessive ion bombardment by ions in the arc plasma. When the temperature of the base material surface is excessively high, sp ³ -C in the grown film is re-transformed into more stable sp ² -C in a state of thermal equilibrium, and as a result, sp ³ -C
Formation of sp ² -C domain than -C domain is considered to become predominant.

As a result of observing the surface with an atomic force microscope, the samples of Examples 1 to 12 and Comparative Examples 1 and 2 showed almost no particles having a particle size of 0.1 μm or more on the surface. It was found that the surface was smooth. On the other hand, in the sample of Comparative Example 3 manufactured without using the protective plate 5, particles having a particle size on the order of μm were observed on the surface, and it was found that the surface was inferior in smoothness.
It was found that the effect of the protection plate 5 was greater than this.

[0065]

According to the method for producing a hard thin film of the present invention, a hard thin film is required for a member or the like which is required to have characteristics such as high hardness, high lubricity, high adhesion resistance, high wear resistance, and high surface smoothness. By forming, the mechanical properties of such a member can be improved. Further, in this manufacturing method, the thin film forming process is simple, the manufacturing apparatus is simple, and the control of manufacturing conditions in the manufacturing process is relatively easy, so that a hard thin film can be easily manufactured. Further, since a hard thin film can be produced at high speed and reliably, mass production with a high yield can be achieved. Further, the materials used in the present manufacturing method are inexpensive, and the manufacturing equipment is relatively inexpensive, so that a hard thin film can be manufactured at low cost. In addition, by greatly expanding the plasma spatially, it is possible to easily form a large-area thin film or to form a thin film on a base material having a three-dimensionally complicated shape.

The hard thin film of the present invention has extremely high hardness and excellent lubricity, adhesion resistance, abrasion resistance and surface smoothness. It can be used as a hard material and a super-hard material used for coating the tool surface and the like.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an apparatus for producing a hard thin film used in this example.

FIG. 2 is a diagram showing the results of hardness measurement of the samples obtained in Examples 1 to 6 and Comparative Example 1.

FIG. 3 is a diagram showing the results of hardness measurement of the samples obtained in Examples 7 to 12 and Comparative Example 2.

FIG. 4 is a diagram showing N / C ratios for the samples obtained in Examples 7 to 12 and Comparative Example 2.

FIG. 5 is a diagram showing Raman spectra measured by Raman spectroscopy on the samples obtained in Examples 1 to 6 and Comparative Examples 1 and 3.

FIG. 6 is a diagram showing Raman spectra measured by Raman spectroscopy on the samples obtained in Examples 7 to 12 and Comparative Example 2.

FIG. 7 is a diagram showing infrared transmission absorption spectra measured by IR for the samples obtained in Examples 7 to 12 and Comparative Example 2.

[Explanation of symbols]

1: Vacuum container 2: Carbon source 3: Exhaust port 4: Substrate holder 5: Protective body 6: Installation table 7: Substrate 8: DC current source 9: DC voltage source 10: Hydrogen gas supply source 11: Nitrogen gas supply source 12 : Permanent magnet 13: Iron disk 14: Arc plasma 15: Thermocouple

Claims (14)

[Claims] 1. A method for producing a hard thin film by an arc ion plating method using a cathode having a carbon source containing at least carbon and a base material, wherein a negative bias voltage is applied to the base material. The base material is set at a negative potential, and molten carbon particles having a particle size of 0.1 μm or more among the carbon evaporated from the carbon source between the cathode and the base material are formed on the base material. A method for producing a hard thin film, comprising a protective body for preventing deposition. 2. The method according to claim 1, wherein the carbon source is made of graphite. 3. The method according to claim 1, wherein an arc plasma containing at least hydrogen is used. 4. The method according to claim 1, wherein said negative bias voltage is between -50V and -3V.
The method for producing a hard thin film according to claim 3, which is in the range of 00V. 5. The method according to claim 1, wherein an arc plasma containing at least nitrogen is used. 6. The method according to claim 1, wherein said negative bias voltage is between -100 V and-
The method for producing a hard thin film according to claim 5, wherein the voltage is in a range of 400V. 7. The method according to claim 1, wherein an arc plasma containing at least one of helium, neon, argon, krypton, and xenon is used. 8. The arc plasma has a system pressure of 0.01.
The method for producing a hard thin film according to any one of claims 3, 5, and 7, which is not less than Pa and not more than 30 Pa. 9. The method for producing a hard thin film according to claim 1, wherein said protective body is made of at least one of a metal and a ceramic, and is a plate-like protective plate. 10. The method according to claim 1, wherein the protective body is at 0 V or at a positive potential. 11. The method according to claim 1, wherein the carbon is evaporated from the carbon source by using at least one of an electron beam, a laser, and an ion beam. 12. The method according to claim 1, wherein the base material is made of at least one of a metal, a semiconductor, a ceramic, and a resin. 13. A cathode provided with a carbon source containing at least carbon, and a base material, a negative bias voltage is applied to the base material to bring the base material to a negative potential, and Of the carbon that evaporates from the carbon source between the base metal and the base material, 0.1% of the carbon evaporates.
A hard thin film obtained by an arc ion plating method in a state where a protective body for preventing molten carbon particles having a particle diameter of 1 μm or more from being deposited on the base material is provided; ³ hybrid orbital and taking carbon atoms (hereinafter, referred to as sp ³ -C) size of the domains of short-range order bound formed together (hereinafter, sp ³ -C
Referred to as the domain) and a plurality of sp ² hybrid orbital and taking carbon atoms (hereinafter, referred to as sp ² -C) size of the domains of short-range order bound formed together (hereinafter, sp
A carbon bond species (hereinafter referred to as an amorphous carbon network) having a network structure formed by random bonding with a ^2- C domain; and at least a part of carbon atoms constituting the amorphous carbon network. A hard thin film characterized by being an amorphous carbon (aC: H) thin film comprising bonded hydrogen atoms. 14. A cathode provided with a carbon source containing at least carbon, and a base material, a negative bias voltage is applied to the base material to bring the base material to a negative potential, and Of the carbon that evaporates from the carbon source between the base metal and the base material, 0.1% of the carbon evaporates.
A hard thin film obtained by an arc ion plating method in a state where a protective body for preventing molten carbon particles having a particle diameter of 1 μm or more from being deposited on the base material is provided; ³ -C bond and the sp ³ -C domains formed by a plurality of sp ² -C are sp ² -C domain bound formed each other and the amorphous carbon network bound formed randomly to each other An amorphous carbon nitride (aC: N) comprising: a nitrogen atom substituted at least at a part of a carbon atom site constituting the amorphous carbon network.
A hard thin film, which is a thin film.